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Midnight_lightning

Polar Alignment Tools and Gadgets

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Hi,

I have to set up my rig for every session and PA takes too much time and I am only achieving 6 arc min accuracy. (HEQ5)

I would like a faster solution, more accuracy and if at all possible I would like to not have to look through the polar scope.

The PoleMaster looks like the answer, just wondered whether any of you use them , what you think and whether there is anything better?

Thanks

Jon

 

 

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m.tweedy    363

Have a look at SharpCap. Polar alignment in just a few minutes and very very accurate. You do need to look through the polar scope initially 

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gonzostar    173

I use polemaster for my set up. Never regretted it Polar alignment takes less then 10mins. PA can be further "fine" tuned using PHD2 if need be. But i believe it can get within 5 arc mins.

 

Dean

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RayD    1,084

Polemaster is excellent if you have to set up every time and do not want to (or can't) spend the time doing a drift alignment.  For visual of course it's not really necessary, but for AP it is a really good little tool.

People that don't have or use one will all argue that there are other, and usually cheaper, ways of doing it, but you will very rarely see anyone who has used or currently uses one say a bad word about it.

I personally believe it isn't always about doing it the cheapest way, but the way which provides you with the most enjoyment.  This for me means spending time imaging, and not bending in unnatural positions to see through a polar scope.  The Polemaster certainly makes a pretty good alignment very quick, and very easy.

Edited by RayD
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Thanks Michael, that looks like an interesting option although it's aligning the OTA rather than the mount and in my case I'm not sure my OTA is aligned accurately enough to the mount.

I need to check this next session and I guess if the mount and OTA don't correspond I probably ought to do something about it anyway.

Certainly a cheaper option than the Polemaster :)

 

 

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Thanks Ray and Gonzo, good feedback although I would hoping to get quite a bit better than 5 arc-mins as I get 6 arc-mins now just using the polarscope.

Just looking on youtube it seems the Polemaster didn't use auto plate solving when it came out, is that still the case, is it something that might get added?

Jon

 

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RayD    1,084
1 minute ago, Midnight_lightning said:

Thanks Ray and Gonzo, good feedback although I would hoping to get quite a bit better than 5 arc-mins as I get 6 arc-mins now just using the polarscope.

Just looking on youtube it seems the Polemaster didn't use auto plate solving when it came out, is that still the case, is it something that might get added?

Jon

 

I think you'll get much better than that if you adjust carefully, and even do 2 iterations.  I certainly do, and comfortably manage 1800s subs.

Platesolving would only be relevant to your alignment (cone error) I would have thought, with the Polemaster only aligning your mount.  You don't even need you OTA on the mount to use it.

I tend to use the Polemaster on my AVX and AZ EQ6 as they get set up (Mesu is on a pier so I drift align), and then plate solve to align and sync, and off I go.

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Craney    352

I would second m.tweedy on using the 'Polar Align' tool on Sharpcap.  Very useful indeed and cuts out any errors you may have with the 'polarscope' arrangement not being perfectly aligned with the polar axis of the mount.  You need a darkish sky and (I think) a good view of the region around Polaris, which you would need anyway for most of the other methods.  I use a 80mmF5 refractor with a 0.5x reduced to get the optimum FL for the tool to work, but a regular 60mm guider/finder should do the trick.

I have acheved alignment in the order of 'seconds of arc'...... and subs of 300s+ on the back of it.  How true this alignment value is, I don't know, and it does waver a bit even though I do not touch the mount  ( minor seismic activity ??)  but I am very happy with the system and it is transferrable across mounts, if you want to set up a multi-mount session.

 

Sean.

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michaelmorris    1,554
On 04/09/2017 at 22:35, Midnight_lightning said:

Thanks Michael, that looks like an interesting option although it's aligning the OTA rather than the mount and in my case I'm not sure my OTA is aligned accurately enough to the mount.

I need to check this next session and I guess if the mount and OTA don't correspond I probably ought to do something about it anyway.

Certainly a cheaper option than the Polemaster :)

 

 

Sharpcap's polar alignment tool assesses the polar alignment of the mount, not the scope.

I've used it with my lodestar camera attached to my finder/guider and got polar alignment accuracy of a little less than 1 arc minute. It means I can use the same hardware for polar alignment and guiding.

The one disadvantage I have found (with my set up) is that it can't find enough alignment stars in less than dark or hazy conditions. A faster guider would probably help get around this.

Whilst I have never used one myself, I know loads of people rave about how simple the Polemaster is to use and that for most people, alignment is plenty accurate enough for their needs.

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RayD    1,084
12 minutes ago, Midnight_lightning said:

Thanks for all the help and suggestions, I have finally decided on the Polemaster, now just awaiting delivery and a clear night :) 

I think you'll be impressed.  I was skeptical before using one and when I did I was surprised how easy it is to use.

Don't forget of course, the Polemaster isn't a fixed item, it comes off with just a thumbscrew and you can swap it between mounts of different types with just buying the base adaptor plate for that mount.

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Yes, good point. I also have a Star Adventurer which I have barely used. Bought to take on holiday and have lugged it to Mallorca twice but had such high humidity and LP that I didn't use it. When I have used it I found the PA a real pain and it's so easy to nudge on a camera tripod. The Polemaster should really help with this mount so I will be saving up for the adapter if I cant make one of my own.

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Gina    8,029

+1 for PoleMaster - as long as you can see Polaris.

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Thanks Gina.

Polaris is fine, I can see North and Up, everything else is blocked by houses - but I find Up is good for a lot of things :)  Just want to get Rosette this year, may have to go off site.

 

 

 

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My Polemaster arrived Friday and my initial reaction is that it is a thing of beauty, just so nicely made, real quality.

Used it last night for the first time and I wish I had bought one earlier, so much easier than trying to look though a Polar scope!

After doing PA I ran Guiding Assistant in PHD and it reported PA within 0.7 Arc Min, I'm not quite sure how that works as the seeing would have been worse but I generally only got 6 arc min via the polar scope so I'm happy.

My guiding was the best ever for the first hour (RMS varied between 0.6 and 0.8) but then went pretty awful as the session went on - something that happens often and I still haven't worked out why, but definitely a thumbs up for PoleMaster.

 

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newbie alert    164
11 hours ago, Midnight_lightning said:

My Polemaster arrived Friday and my initial reaction is that it is a thing of beauty, just so nicely made, real quality.

Used it last night for the first time and I wish I had bought one earlier, so much easier than trying to look though a Polar scope!

After doing PA I ran Guiding Assistant in PHD and it reported PA within 0.7 Arc Min, I'm not quite sure how that works as the seeing would have been worse but I generally only got 6 arc min via the polar scope so I'm happy.

My guiding was the best ever for the first hour (RMS varied between 0.6 and 0.8) but then went pretty awful as the session went on - something that happens often and I still haven't worked out why, but definitely a thumbs up for PoleMaster.

 

Great news on the polemaster..certainly is fast to align but as you can see it's easy to have errors...I initially use polemaster to align then load up sharpcap and tweak the alignment further still..try it and see

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I think the PA was fine as the guiding was excellent for the first hour, just not sure what happened after that, most probably due to the balance changing on the Scope as the target ascended, but really not sure.

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billyharris72    301
On 06/09/2017 at 07:55, michaelmorris said:

Sharpcap's polar alignment tool assesses the polar alignment of the mount, not the scope.

Not strictly true from what I have seen.

Having reread this mid way through composing my reply - strictly true from what I have seen!

Sharp Cap takes two images and uses its astrometry to model the axis of rotation of the scope - that is the alignment of the mount itself rather than the scope. Issues like cone error don't affect the results at all, provided it is not so far out that you can't place Polaris in the image (a problem I have had to content with).

I find I can get error down to less than one minute with about 5 minutes of fiddling - it's been an abolutle godsend since I figured out how to use it.

Billy.

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kirkster501    1,437

6 mins of arc accuracy is pretty good anyway.  EQMod's method is also a superb way to get the PA very accurate.

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ollypenrice    16,821

One way to spend less time uncomfortably looking through the polar scope is simply to shine a laser pointer through it and look where it's aiming. It isn't an accurate first step but it's an adequate one and saves strain on the poor old neck. 

Oly

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